Disclosed herein are methods for preparing high performance photosensitive polyarylene ether polymers. More specifically, disclosed herein are methods for preparing high performance photosensitive polyarylene ether polymers from haloalkylated intermediate polymers, wherein the resulting photosensitive polymers have a desirably low halogen content and, when cured, exhibit a desirably low crosslink density. One embodiment is directed to a polymer of the formula wherein x is an integer of 0 or 1, n is an integer representing the number of repeating monomer units, each of R1, R2, R3, and R4, independently of the others, is an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group, each of X1, X2, X3, and X4, independently of the others, is a halogen atom, a′, b′, c′, and d′ are each, independently of the others, integers of 0, 1, 2, 3, or 4, each UE group, independently of the others, is an unsaturated ester group, e, f, g, and h are each, independently of the others, integers of 0, 1, 2, 3, or 4, provided that at least one of e, f, g, and h is equal to or greater than 1 in at least some of the monomer repeat units of the polymer, each SE group, independently of the others, is a saturated ester group, and i, j, k, and m are each, independently of the others, integers of 0, 1, 2, 3, or 4, provided that at least one of i, j, k, and m is equal to or greater than 1 in at least some of the monomer repeat units of the polymer, provided that the sum of a′+e+i is less than or equal to 4, provided that the sum of b′+f+j is less than or equal to 4, provided that the sum of c′+g+k is less than or equal to 4, and provided that the sum of d′+h+m is less than or equal to 4, A is wherein R is a hydrogen atom, an alkyl group, an aryl group, an arylalkyl group, an alkylaryl group, or mixtures thereof, or mixtures thereof, B is wherein v is an integer of from 1 to about 20,—(CH2O)t—wherein t is an integer of from 1 to about 20, wherein z is an integer of from 2 to about 20, wherein u is an integer of from 1 to about 20, wherein w is an integer of from 1 to about 20, wherein Ra and Rb each, independently of the other, are hydrogen atoms, alkyl groups, aryl groups, arylalkyl groups, alkylaryl groups, or mixtures thereof, and p is an integer of 0 or 1, wherein r is an integer of 0 or 1, wherein (1) Z is wherein y is o or 1; (2) Ar is (3) G is an alkyl group selected from alkyl or isoalkyl groups containing from about 2 to about 10 carbon atoms; (4) Ar′ is and (6) q is 0 or 1; or mixtures thereof, wherein RX represents the total number of haloalkyl groups in the polymer and is the sum of all R1X1 groups+all R2X2 groups+all R3X3 groups+all R4X4 groups, and wherein the ratio of unsaturated groups to saturated groups to RX groups in the polymer is represented byυε:σε:ρχwherein υε is from about 1 to about 99.99, wherein σε is from about 0.01 to about 99, wherein ρχ is from 0 to about 50, and wherein υε+σε+ρχ=100. Another embodiment is directed to a process for preparing a photosensitive polymer which comprises reacting a haloalkylated precursor polymer of the formula wherein x is an integer of 0 or 1, n is an integer representing the number of repeating monomer units, each of R1, R2, R3, and R4, independently of the others, is an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group, each of X1, X2, X3, and X4, independently of the others, is a halogen atom, a, b, c, and d are each integers of 0, 1, 2, 3, or 4, provided that at least one of a, b, c, and d is equal to or greater than 1 in at least some of the monomer repeat units of the polymer, A is wherein R is a hydrogen atom, an alkyl group, an aryl group, an arylalkyl group, an alkylaryl group, or mixtures thereof, wherein v is an integer of from 1 to about 20,—(CH2O)t—wherein t is an integer of from 1 to about 20, wherein z is an integer of from 2 to about 20, wherein u is an integer of from 1 to about 20, wherein w is an integer of from 1 to about 20, wherein Ra and Rb each, independently of the other, are hydrogen atoms, alkyl groups, aryl groups, arylalkyl groups, alkylaryl groups, or mixtures thereof, and p is an integer of 0 or 1, wherein r is an integer of 0 or 1, wherein (1) Z is wherein y is 0 or 1; (2) Ar is (3) G is an alkyl group selected from alkyl or isoalkyl groups containing from about 2 to about 10 carbon atoms; (4) Ar′ is and (6) q is 0 or 1; or mixtures thereof, with an unsaturated ester salt and a saturated ester salt, thereby forming a curable polymer of the formula wherein a′, b′, c′, and d′ are each, independently of the others, integers of 0, 1, 2, 3, or 4, each UE group, independently of the others, is an unsaturated ester group corresponding to the unsaturated ester salt, e, f, g, and h are each, independently of the others, integers of 0, 1, 2, 3, or 4, provided that at least one of e, f, g, and h is equal to or greater than 1 in at least some of the monomer repeat units of the polymer, each SE group, independently of the others, is a saturated ester group corresponding to the saturated ester salt, and i, j, k, and m are each, independently of the others, integers of 0, 1, 2, 3, or 4, provided that at least one of i, j, k, and m is equal to or greater than 1 in at least some of the monomer repeat units of the polymer, provided that the sum of a′+e+i is less than or equal to 4, provided that the sum of b′+f+j is less than or equal to 4, provided that the sum of c′+g+k is less than or equal to 4, and provided that the sum of d′+h+m is less than or equal to 4, wherein RX represents the total number of haloalkyl groups in the polymer and is the sum of all R1X1 groups+all R2X2 groups+all R3X3 groups+all R4X4 groups, wherein the ratio of unsaturated ester salt to saturated ester salt is selected so that in the resulting polymer the ratio of unsaturated ester groups to saturated ester groups to RX groups in the polymer is represented byυε:σε:ρχwherein υε is from about 1 to about 99.99, wherein σε is from about 0.01 to about 99, wherein ρχ is from 0 to about 50, and wherein υε:σε:ρχ=100.
In microelectronics applications, there is a great need for low dielectric constant, high glass transition temperature, thermally stable, photopatternable polymers for use as interlayer dielectric layers and as passivation layers which protect microelectronic circuitry. Poly(imides) are widely used to satisfy these needs; these materials, however, have disadvantageous characteristics such as relatively high water sorption and hydrolytic instability. There is thus a need for high performance polymers which can be effectively photopatterned and developed at high resolution.
Polyarylene ethers are known polymers for use as high performance engineering thermoplastics. They exhibit outstanding physical properties and high chemical resistance. The use of these materials as photoresists when substituted with photoactive substituents is also known. These materials are suitable for use in applications such as thermal ink jet printheads, other microelectronics applications, printed circuit boards, lithographic printing processes, interlayer dielectrics, and the like.
U.S. Pat. No. 5,994,425 (Narang et al.), U.S. Pat. No. 6,022,095 (Narang et al.), EP 827027, and JP 10120743, the disclosures of each of which are totally incorporated herein by reference, disclose an improved composition comprising a photopatternable polymer containing at least some monomer repeat units with photosensitivity-imparting substituents, said photopatternable polymer being of the general formula wherein x is an integer of 0 or 1, A is one of several specified groups, such as B is one of several specified groups, such as or mixtures thereof, and n is an integer representing the number of repeating monomer units. Also disclosed is a process for preparing a thermal ink jet printhead with the aforementioned polymer and a thermal ink jet printhead containing therein a layer of a crosslinked or chain extended polymer of the above formula.
U.S. Pat. No. 5,849,809 (Narang et al.), U.S. Pat. No. 6,203,143 (Narang et al.), EP 827028, and JP 10090895, the disclosures of each of which are totally incorporated herein by reference, disclose a composition which comprises (a) a polymer containing at least some monomer repeat units with photosensitivity-imparting substituents which enable crosslinking or chain extension of the polymer upon exposure to actinic radiation, said polymer being of the formula wherein x is an integer of 0 or 1, A is one of several specified groups, such as B is one of several specified groups, such as or mixtures thereof, and n is an integer representing the number of repeating monomer units, wherein said photosensitivity-imparting substituents are hydroxyalkyl groups; (b) at least one member selected from the group consisting of photoinitiators and sensitizers; and (c) an optional solvent. Also disclosed are processes for preparing the above polymers and methods of preparing thermal ink jet printheads containing the above polymers.
U.S. Pat. No. 6,124,372 (Smith et al.), U.S. Pat. No. 6,151,042 (Smith et al.), U.S. Pat. No. 6,323,301 (Smith et al.), EP 827029, and JP 10097073, the disclosures of each of which are totally incorporated herein by reference, disclose a composition comprising a polymer with a weight average molecular weight of from about 1,000 to about 100,000, said polymer containing at least some monomer repeat units with a first, photosensitivity-imparting substituent which enables crosslinking or chain extension of the polymer upon exposure to actinic radiation, said polymer also containing a second, thermal sensitivity-imparting substituent which enables further crosslinking or chain extension of the polymer upon exposure to temperatures of about 140° C. and higher, wherein the first substituent is not the same as the second substituent, said polymer being selected from the group consisting of polysulfones, polyphenylenes, polyether sulfones, polyimides, polyamide imides, polyarylene ethers, polyphenylene sulfides, polyarylene ether ketones, phenoxy resins, polycarbonates, polyether imides, polyquinoxalines, polyquinolines, polybenzimidazoles, polybenzoxazoles, polybenzothiazoles, polyoxadiazoles, copolymers thereof, and mixtures thereof.
U.S. Pat. No. 5,889,077 (Fuller et al.), U.S. Pat. No. 6,087,414 (Fuller et al.), EP 827030, and JP 10090894, the disclosures of each of which are totally incorporated herein by reference, disclose a process which comprises reacting a polymer of the general formula wherein x is an integer of 0 or 1, A is one of several specified groups, such as B is one of several specified groups, such as or mixtures thereof, and n is an integer representing the number of repeating monomer units, with (i) a formaldehyde source, and (ii) an unsaturated acid in the presence of an acid catalyst, thereby forming a curable polymer with unsaturated ester groups. Also disclosed is a process for preparing an ink jet printhead with the above polymer.
U.S. Pat. No. 5,739,254 (Fuller et al.), U.S. Pat. No. 5,753,783 (Fuller et al.), EP 826700, and JP 10087817, the disclosures of each of which are totally incorporated herein by reference, disclose a process which comprises reacting a polymer of the general formula wherein x is an integer of 0 or 1, A is one of several specified groups, such as B is one of several specified groups, such as or mixtures thereof, and n is an integer representing the number of repeating monomer units, with an acetyl halide and dimethoxymethane in the presence of a halogen-containing Lewis acid catalyst and methanol, thereby forming a haloalkylated polymer. In a specific embodiment, the haloalkylated polymer is then reacted further to replace at least some of the haloalkyl groups with photosensitivity-imparting groups. Also disclosed is a process for preparing a thermal ink jet printhead with the aforementioned polymer.
U.S. Pat. No. 5,761,809 (Fuller et al.), EP 827026, and JP 10090896, the disclosures of each of which are totally incorporated herein by reference, disclose a process which comprises reacting a haloalkylated aromatic polymer with a material selected from the group consisting of unsaturated ester salts, alkoxide salts, alkylcarboxylate salts, and mixtures thereof, thereby forming a curable polymer having functional groups corresponding to the selected salt. Another embodiment is directed to a process for preparing an ink jet printhead with the curable polymer thus prepared.
U.S. Pat. No. 5,958,995 (Narang et al.), U.S. Pat. No. 6,184,263 (Narang et al.), EP 827031, and JP 10104836, the disclosures of each of which are totally incorporated herein by reference, disclose a composition which comprises a mixture of (A) a first component comprising a polymer, at least some of the monomer repeat units of which have at least one photosensitivity-imparting group thereon, said polymer having a first degree of photosensitivity-imparting group substitution measured in milliequivalents of photosensitivity-imparting group per gram and being of the general formula wherein x is an integer of 0 or 1, A is one of several specified groups, such as B is one of several specified groups, such as or mixtures thereof, and n is an integer representing the number of repeating monomer units, and (B) a second component which comprises either (1) a polymer having a second degree of photosensitivity-imparting group substitution measured in milliequivalents of photosensitivity-imparting group per gram lower than the first degree of photosensitivity-imparting group substitution, wherein said second degree of photosensitivity-imparting group substitution may be zero, wherein the mixture of the first component and the second component has a third degree of photosensitivity-imparting group substitution measured in milliequivalents of photosensitivity-imparting group per gram which is lower than the first degree of photosensitivity-imparting group substitution and higher than the second degree of photosensitivity-imparting group substitution, or (2) a reactive diluent having at least one photosensitivity-imparting group per molecule and having a fourth degree of photosensitivity-imparting group substitution measured in milliequivalents of photosensitivity-imparting group per gram, wherein the mixture of the first component and the second component has a fifth degree of photosensitivity-imparting group substitution measured in milliequivalents of photosensitivity-imparting group per gram which is higher than the first degree of photosensitivity-imparting group substitution and lower than the fourth degree of photosensitivity-imparting group substitution; wherein the weight average molecular weight of the mixture is from about 10,000 to about 50,000; and wherein the third or fifth degree of photosensitivity-imparting group substitution is from about 0.25 to about 2 milliequivalents of photosensitivity-imparting groups per gram of mixture. Also disclosed is a process for preparing a thermal ink jet printhead with the aforementioned composition.
U.S. Pat. No. 5,945,253 (Narang et al.), U.S. Pat. No. 6,365,323 (Narang et al.), EP 827033, and JP 10090897, the disclosures of each of which are totally incorporated herein by reference, disclose a composition which comprises a polymer containing at least some monomer repeat units with photosensitivity-imparting substituents which enable crosslinking or chain extension of the polymer upon exposure to actinic radiation, said polymer being of the formula wherein x is an integer of 0 or 1, A is one of several specified groups, such as B is one of several specified groups, such as or mixtures thereof, and n is an integer representing the number of repeating monomer units, wherein said photosensitivity-imparting substituents are allyl ether groups, epoxy groups, or mixtures thereof. Also disclosed are a process for preparing a thermal ink jet printhead containing the aforementioned polymers and processes for preparing the aforementioned polymers.
U.S. Pat. No. 5,863,963 (Narang et al.), U.S. Pat. No. 6,090,453 (Narang et al.), and JP 10090899, the disclosures of each of which are totally incorporated herein by reference, disclose a process which comprises the steps of (a) providing a polymer containing at least some monomer repeat units with halomethyl group substituents which enable crosslinking or chain extension of the polymer upon exposure to a radiation source which is electron beam radiation, x-ray radiation, or deep ultraviolet radiation, said polymer being of the formula wherein x is an integer of 0 or 1, A is one of several specified groups, such as B is one of several specified groups, such as or mixtures thereof, and n is an integer representing the number of repeating monomer units, and (b) causing the polymer to become crosslinked or chain extended through the photosensitivity-imparting groups. Also disclosed is a process for preparing a thermal ink jet printhead by the aforementioned curing process.
U.S. Pat. No. 6,007,877 (Narang et al.), U.S. Pat. No. 6,273,543 (Narang et al.), EP 827032, and JP 10090898, the disclosures of each of which are totally incorporated herein by reference, disclose a composition which comprises a polymer containing at least some monomer repeat units with water-solubility- or water-dispersability-imparting substituents and at least some monomer repeat units with photosensitivity-imparting substituents which enable crosslinking or chain extension of the polymer upon exposure to actinic radiation, said polymer being of the formula wherein x is an integer of 0 or 1, A is one of several specified groups, such as B is one of several specified groups, such as or mixtures thereof, and n is an integer representing the number of repeating monomer units. In one embodiment, a single functional group imparts both photosensitivity and water solubility or dispersability to the polymer. In another embodiment, a first functional group imparts photosensitivity to the polymer and a second functional group imparts water solubility or dispersability to the polymer. Also disclosed is a process for preparing a thermal ink jet printhead with the aforementioned polymers.
U.S. Pat. No. 5,814,426 (Fuller et al.), EP 918257, and JP 11218943, the disclosures of each of which are totally incorporated herein by reference, disclose an imaging member which comprises a conductive substrate, a photogenerating material, and a binder which comprises a polymer of the formulae I, II, III, IV, V, VI, VII, VIII, IX, or X as further defined therein.
U.S. Pat. No. 5,882,814 (Fuller et al.), EP 918256, and JP 11223956, the disclosures of each of which are totally incorporated herein by reference, disclose an imaging member which comprises a conductive substrate, a photogenerating layer, and a charge transport layer comprising a polymer of the formulae I, II, III, IV, V, VI, VII, VIII, IX, or X as further defined therein.
U.S. Pat. No. 5,874,192 (Fuller et al.), EP 918258, and JP 11223955, the disclosures of each of which are totally incorporated herein by reference, disclose an imaging member which comprises a conductive substrate, a photogenerating material, a charge transport material, and a polymeric binder comprising (a) a first polymer comprising a polycarbonate, and (b) a second polymer of the formulae I, II, III, IV, V, VI, VII, VIII, IX, or X as further defined therein.
U.S. Pat. No. 6,273,985 (DeLouise et al.), the disclosure of which is totally incorporated herein by reference, discloses a process for bonding a first article to a second article which comprises (a) providing a first article comprising a polymer having photosensitivity-imparting substituents; (b) providing a second article comprising metal, plasma nitride, silicon, or glass; (c) applying to at least one of the first article and the second article an adhesion promoter selected from silanes, titanates, or zirconates having (i) alkoxy, aryloxy, or arylalkyloxy functional groups and (ii) functional groups including at least one photosensitive aliphatic >C═C< linkage; (d) placing the first article in contact with the second article; and (e) exposing the first article, second article, and adhesion promoter to radiation, thereby bonding the first article to the second article with the adhesion promote. In one embodiment, the adhesion promoter is employed in microelectrical mechanical systems such as thermal ink jet printheads.
U.S. Pat. No. 6,260,956 (Narang et al.), the disclosure of which is totally incorporated herein by reference, discloses an ink jet printhead which comprises (i) an upper substrate with a set of parallel grooves for subsequent use as ink channels and a recess for subsequent use as a manifold, the grooves being open at one end for serving as droplet emitting nozzles, and (ii) a lower substrate in which one surface thereof has an array of heating elements and addressing electrodes formed thereon, said lower substrate having an insulative layer deposited on the surface thereof and over the heating elements and addressing electrodes and patterned to form recesses therethrough to expose the heating elements and terminal ends of the addressing electrodes, the upper and lower substrates being aligned, mated, and bonded together to form the printhead with the grooves in the upper substrate being aligned with the heating elements in the lower substrate to form droplet emitting nozzles, said upper substrate comprising a material formed by crosslinking or chain extending a polymer of formula I or II.
U.S. Pat. No. 6,117,967 (Fuller et al.) and JP 200119761, the disclosures of each of which are totally incorporated herein by reference, discloses a polymer of the formula wherein R is a hydrogen atom, an alkyl group, an aryl group, or mixtures thereof, B is one of specified groups, such as or mixtures thereof, and n is an integer representing the number of repeating monomer units.
U.S. Pat. No. 6,177,238 (Fuller et al.), the disclosure of which is totally incorporated herein by reference, discloses an ink jet printhead containing a polymer of the formula wherein P is a substituent which enables crosslinking of the polymer, a, b, c, and d are each integers of 0, 1, 2, 3, or 4, provided that at least one of a, b, c, and d is equal to or greater than 1 in at least some of the monomer repeat units of the polymer, A is wherein R is a hydrogen atom, an alkyl group, an aryl group, or mixtures thereof, B is one of specified groups, such as or mixtures thereof, and n is an integer representing the number of repeating monomer units.
U.S. Pat. No. 6,174,636 (Fuller et al.), the disclosure of which is totally incorporated herein by reference, discloses an imaging member which comprises a conductive substrate, a photogenerating material, and a binder comprising a polymer of the formula wherein R is a hydrogen atom, an alkyl group, an aryl group, or mixtures thereof, B is one of specified groups, such as or mixtures thereof, and n is an integer representing the number of repeating monomer units.
U.S. Pat. No. 6,187,512 (Foucher et al.) and JP 2000344884, the disclosures of each of which are totally incorporated herein by reference, disclose a process which comprises reacting a polymer of the general formula wherein x is an integer of 0 or 1, A is one of several specified groups, such as B is one of several specified groups, such as or mixtures thereof, and n is an integer representing the number of repeating monomer units, with a halomethyl alkyl ether, an acetyl halide, and methanol in the presence of a halogen-containing Lewis acid catalyst, thereby forming a halomethylated polymer.
U.S. Pat. No. 6,020,119 (Foucher et al.), the disclosure of which is totally incorporated herein by reference, discloses a process which comprises reacting a polymer of the general formula wherein x is an integer of 0 or 1, A is one of several specified groups, such as B is one of several specified groups, such as or mixtures thereof, and n is an integer representing the number of repeating monomer units, with a halomethylethyl ether, a hydrohalic acid, and acetic acid in the presence of a halogen-containing Lewis acid catalyst, thereby forming a halomethylated polymer.
U.S. Pat. No. 6,139,920 (Smith et al.) and U.S. Pat. No. 6,260,949 (Smith et al.), the disclosures of each of which are totally incorporated herein by reference, disclose a composition comprising a blend of (a) a thermally reactive polymer selected from the group consisting of resoles, novolacs, thermally reactive polyarylene ethers, and mixtures thereof; and (b) a photoreactive epoxy resin that is photoreactive in the absence of a photocationic initiator.
U.S. Pat. No. 5,773,553 (Fuller et al.) and U.S. Pat. No. 5,869,595 (Fuller et al.), the disclosures of each of which are totally incorporated herein by reference, disclose a process which comprises reacting a polyimide precursor with borane. Also disclosed is a thermal ink jet printhead containing a layer comprising the product of this reaction.
U.S. Pat. No. 5,939,206 (Kneezel et al.) and JP 10100410, the disclosures of each of which are totally incorporated herein by reference, disclose an apparatus which comprises at least one semiconductor chip mounted on a substrate, said substrate comprising a porous, electrically conductive member having electrophoretically deposited thereon a coating of a polymeric material. In one embodiment, the semiconductor chips are thermal ink jet printhead subunits.
U.S. Pat. No. 6,485,130 (DeLouise et al.), the disclosure of which is totally incorporated herein by reference, discloses a process for bonding a first article to a second article which comprises (a) providing a first article comprising a polymer having photosensitivity-imparting substituents; (b) providing a second article comprising metal, plasma nitride, silicon, or glass; (c) applying to at least one of the first article and the second article an adhesion promoter selected from silanes, titanates, or zirconates having (i) alkoxy, aryloxy, or arylalkyloxy functional groups and (ii) functional groups including at least one photosensitive aliphatic >C═C< linkage; (d) placing the first article in contact with the second article; and (e) exposing the first article, second article, and adhesion promoter to radiation, thereby bonding the first article to the second article with the adhesion promote. In one embodiment, the adhesion promoter is employed in microelectrical mechanical systems such as thermal ink jet printheads.
While known compositions and processes are suitable for their intended purposes, a need remains for improved materials suitable for microelectronics applications. A need also remains for photopatternable polymeric materials which are heat stable, electrically insulating, and mechanically robust. Further, a need remains for photopatternable polymeric materials which exhibit low shrinkage during post-cure steps in microelectronic device fabrication processes. In addition, a need remains for photopatternable polymeric materials which exhibit a relatively long shelf life. There is also a need for photopatternable polymeric materials which can be patterned with relatively low photo-exposure energies. In addition, there is a need for photopatternable polymeric materials which, in the cured form, exhibit good solvent resistance. Further, there is a need for photopatternable polymeric materials which, when applied to microelectronic devices by spin casting techniques and cured, exhibit reduced edge bead and no apparent lips and dips. Additionally, there is a need for processes for preparing photopatternable polymeric materials with high aspect ratios at high resolutions by the incorporation of polymerizable groups and/or cross-linking sites pendant to the polymers. A need also remains for processes for preparing photopatternable polymers from intermediate polymers having halomethyl groups pendant to the polymer chains wherein the resulting photopatternable polymers exhibit a desirably low halogen content. In addition, a need remains for processes for preparing photopatternable polymers from intermediate polymers having halomethyl groups pendant to the polymer chains wherein the resulting photopatternable polymers, when cured, exhibit a desirably low crosslink density. Further, a need remains for processes for preparing photopatternable polymers from intermediate polymers having halomethyl groups pendant to the polymer chains wherein the synthesis of the photopatternable polymers takes place within a reasonably short period of time. Additionally, a need remains for processes for preparing photopatternable polymers from intermediate polymers having halomethyl groups pendant to the polymer chains wherein the resulting photopatternable polymer does not cause corrosion in unprotected parts of a microelectronic device. There is also a need for processes for preparing photopatternable polymers from intermediate polymers having halomethyl groups pendant to the polymer chains wherein the resulting photopatternable polymer does not cause corrosion in unprotected equipment used in the fabrication and processing of microelectronic devices. In addition, there is a need for processes for preparing photopatternable polymers from intermediate polymers having halomethyl groups pendant to the polymer chains wherein the formulation and processing of the photopatternable polymer does not result in unnecessary exposure of workers to residual hazardous chemicals such as chlorine gas.